Riff

A riff is a short, repeated motif or figure in the melody or accompaniment of a musical composition. Riffs are most often found in various genres of rock music, as well as Latin, funk, and jazz, although classical music is also sometimes based on a riff, as in Ravel's Boléro. Riffs can be as simple as a tenor saxophone honking a simple, catchy rhythmic figure, or as complex as the riff-based varia... (Wikipedia)